Understanding glibc malloc

I always got fascinated by heap memory. Questions such as

How heap memory is obtained from kernel?
How efficiently memory is managed?
Is it managed by kernel or by library or by application itself?
Can heap memory be exploited?

were in my mind for quite some time. But only recently I got time to understand about it. So here I would like to share my fascination turned knowledge!! Out there in the wild, many memory allocators are available:

• dlmalloc – General purpose allocator
• ptmalloc2 – glibc
• jemalloc – FreeBSD and Firefox
• tcmalloc – Google
• libumem – Solaris
• …

Every memory allocator claims they are fast, scalable and memory efficient!! But not all allocators can be suited well for our application. Memory hungry application’s performance largely depends on memory allocator performance. In this post, I will only talk about ‘glibc malloc’ memory allocator. In future, I am hoping to cover up other memory allocators. Throughout…